1. Field of the Invention
The present invention relates to a stopwatch for measuring a lapse time and, more particularly, to a stopwatch for measuring a lap time by a switching operation and for displaying information regarding the measured lap time.
2. Description of the Related Art
A stopwatch, which informs an operator that a measured time arrives at a preset target time or displays a time difference between the target time and the measured time, has been widely known. For example, a stopwatch of this type is disclosed in U.S. Pat. No. 4,831,605. The stopwatch of this type is used in the field of motor sport.
In a motor car race in which motor cars run in a circuit many times, it is desired to know whether the speed of an aimed motor car raises or lowers at every one lap or not, or to know the raised or lowered degree of a measured lap time when it is compared to a target time. In a conventional stopwatch in which a target time can be set, it is remarkably troublesome to know the above described data. In the conventional stopwatch, at first an operator expects a target time in which an aimed motor car runs in a racing course for one time, and then sets the target time, for example, three minutes. After that, the difference between the measured lap time and the target time is calculated to know whether the speed of the aimed motor car raises or lowers at one lap, and then the raised or lowered degree of the measured lap time to the target time at one lap is calculated on the basis of the above described time difference. If the preceding lap time is, for example, +10 seconds with respect to the three minutes and the present lap time is, for example, +2 seconds to the three minutes, the present lap time is shorter than the preceding lap time by +8 seconds. If, however, the preceding lap time is not remembered, an operator can not know the time difference between the present lap time and the preceding lap time. Further, since the present lap time is displayed as "+2 seconds", there is the possibility that the operator misunderstands that the present lap time is longer than the preceding lap time by +2 seconds.